Should Riot Buff up Liandrys Torment?

feels like a very underwhelming item. It gives decent stats IMO, some mpen, health and AP. However, its passive seems really bad, even if boosted when applied to a slowed target, it seems like it doesn't do anything or close to anything, it just feels like stopping the enemy health regen for 2 seconds. Has anyone else thought this item needs to get better? It's quite expensive for an underwhelming passive.

Edit: thanks for your opinions and info. After reading a bit guess it is a good item with the right champion. For example I like it on Galio, since his Q applies a slow for a stronger effect and you can spam Q almost every 4 seconds, but it doesn't seem to do much, hence my question. Maybe I couldve been biased here?